When you go searching for a product on Amazon, you might assume that people reviewing microwaves and food processors and vacuums are regular consumers who just want to share their opinions with the masses after purchasing a product.

This is not always the case.

In NPR's report:

Erb is a member of Amazon Vine, an invitation-only program for the site's top reviewers. At least once a month, Amazon sends Erb a list of products. He gets to choose any two items from the list. "My only obligation is that I need to write a review of those two items within 30 days," Erb told me. "And I get to keep the items after I review them."

The rules: Erb can't sell the products or give them away because Amazon can ask for the stuff back at anytime. In the five years Erb has been a member of Amazon Vine, he has never been asked to return anything.

A spokesperson for Amazon told NPR:

The Vine program was created to deal with some of the inherent challenges in customer reviews. For example, if someone has a bad experience with shipping or a particular seller, their review may be more about that specific experience than about the product itself. So Amazon works with the site's most trusted reviewers to populate the site with more useful reviews. Even a product with negative reviews sells better than a product with no reviews at all.